To make portable electronic appliances, such as mobile phones or portable multimedia players (PMPs), compact and light, back-lap or back-grinding processes for wafers may be used. A back-grinding process may remove a portion of a back side of a wafer, on which side integrated circuits are not formed, to reduce a thickness of the wafer using a laser, chemical and/or mechanical polishing. After the back-grinding process, subsequent processes, such as attaching a circuit substrate, making electrical connections, sealing processes, forming input/output terminals, and sawing processes, may be performed to manufacture a semiconductor package including the wafer.